文件对象

这些 API 是用于内置文件对象的 Python 2 C API 的最小仿真，使用依赖缓冲 I/O ( FILE * ) 支持来自 C 标准库。在 Python 3，文件和流使用新 io 模块，其在 OS 低级无缓冲 I/O 之上定义了几个层。下文描述的函数是这些新 API 之上的方便 C 包裹器，且主要意味着解释器报告的内部错误；建议第 3 方代码访问 io API 代之。

PyObject * PyFile_FromFd ( int fd , const char * 名称 , const char * mode , int buffering , const char * encoding , const char * errors , const char * newline , int closefd )
返回值：新引用。 属于 稳定 ABI (应用程序二进制接口) .

Create a Python file object from the file descriptor of an already opened file fd 。自变量 name , encoding , errors and newline 可以是 NULL to use the defaults; buffering 可以是 -1 to use the default. name is ignored and kept for backward compatibility. Return NULL on failure. For a more comprehensive description of the arguments, please refer to the io.open() function documentation.

警告

Since Python streams have their own buffering layer, mixing them with OS-level file descriptors can produce various issues (such as unexpected ordering of data).

3.2 版改变： 忽略 name 属性。

int PyObject_AsFileDescriptor ( PyObject * p )
属于 稳定 ABI (应用程序二进制接口) .

Return the file descriptor associated with p as an int . If the object is an integer, its value is returned. If not, the object’s fileno() method is called if it exists; the method must return an integer, which is returned as the file descriptor value. Sets an exception and returns -1 当故障时。

PyObject * PyFile_GetLine ( PyObject * p , int n )
返回值：新引用。 属于 稳定 ABI (应用程序二进制接口) .

相当于 p.readline([n]) , this function reads one line from the object p . p may be a file object or any object with a readline() 方法。若 n is 0 , exactly one line is read, regardless of the length of the line. If n 大于 0 , no more than n bytes will be read from the file; a partial line can be returned. In both cases, an empty string is returned if the end of the file is reached immediately. If n 小于 0 , however, one line is read regardless of length, but EOFError is raised if the end of the file is reached immediately.

int PyFile_SetOpenCodeHook ( Py_OpenCodeHookFunction handler )

覆写正常行为的 io.open_code() 透过提供的处理程序传递它的参数。

The handler is a function of type:

typedef PyObject * ( * Py_OpenCodeHookFunction ) ( PyObject * , void * )

Equivalent of PyObject * ( * ) ( PyObject * path , void * userData ) ，其中 path 保证是 PyUnicodeObject .

The userData 指针会被传入挂钩函数。由于可以从不同运行时调用挂钩函数，此指针不应直接引用 Python 状态。

由于此挂钩是在 import 期间有意使用的，避免导入新模块在其执行期间，除非知道它们被冻结或可用于 sys.modules .

一旦设置挂钩，就无法移除 (或替换) 它，且稍后调用 PyFile_SetOpenCodeHook() 将失败。当故障时，函数返回 -1 并设置异常若解释器已初始化。

调用此函数是安全的先于 Py_Initialize() .

引发 审计事件 setopencodehook 不带自变量。

Added in version 3.8.